Аннотация:
We construct the integrating factor of the differential systems of the form
$\dot x= x+P_n(x,y), \ \dot y=y+Q_n(x,y)$
where $P_n(x,y)$ and $Q_n(x,y)$ are homogeneous polynomials.
Ключевые слова:polynomial systems, integrating factor, polynomial first integrals, rational first integrals, symmetries.